At its simpliest an air well is a structure or a device that collects water from the air using condensation. In the early part of the 1900, a few enterprising men experimented with rock air wells to capture moisture. They were working off the theory ancient cities used stacks of rocks as condensers and terra cotta pipes connected to the city’s water system to supply water for the city.

The stone of well cools during the night. During the day warm air enters near the top and was it cools condensation forms on the rocks walls and drips into a basin at the bottom. The air well produced about 5 gallons of water a night. There was a write up on the air well in the 1933 issue of Popular Science, you can check it out here. There is a great illustration of the inside of the air well. It is about halfway through the magazine.

People are using this same principle to capture dew off of their roofs in India. Adding a bit of insulation gets even better results. The set up seems very similar to regular water catchment from a roof.

Some of the simplest designs are a pile of rocks. These stone piles cool in the night air and when the warm daytime air hits the rock it condenses and drips down into the rock pile, watering whatever plants you have nearby. This technique (and picture) are discussed in this PRI article.

Companies are creating water makers that convert air into drinking water using technology similar to a dehumidifier with the hope to provide water for entire villages were water scarcity is a real and daily problem. There is a great write up about it here.

I think these techniques have great possibilities in greening the deserts and saving lives. Is there any Permies out there that are using air wells?

This must be where Frank Herbert got the idea for "wind tunnel moisture traps" used by the Fremen in the "Dune" books. I always wondered how possible it was for that to actually work.

Amber Beckerson

Joined: Nov 24, 2012
Posts: 2

posted Apr 05, 2013 21:07:08

1

I wonder if you'd get more water collection if you used metal condensers inside of the rock pile. They would certainly be colder than the rocks surrounding them. Copper or stainless steel would probably be the best choices for the cleanest water, but if you're just watering plants, steel pipes would probably work well enough.

I built my porch roofs sloping back to the gutter to collect the rain water. They are dark green on the top and white underneath They cool by radiation during the night and are coated with dew underneath in the morning but I did not make them steep enough to drip the dew into the gutter so it drips on the porch.

Growing up as a kid, I would often see a big field with a huge tree that had a pile of rocks next to it. I wonder if the old timers knew to do that to help water the tree during the summers.

And I think I'll start stacking rocks next to all my fruit trees. Should also help to even out temps in the winter just a bit. I have an olive tree that is just barely supposed to make it through our winters, the rocks my be just enough thermal mass to always see it through.

Amber Beckerson wrote:I wonder if you'd get more water collection if you used metal condensers inside of the rock pile. They would certainly be colder than the rocks surrounding them. Copper or stainless steel would probably be the best choices for the cleanest water, but if you're just watering plants, steel pipes would probably work well enough.

And that's why this technique is generally useless in areas that are deserts. Not enough humidity in the air to make it work. For me, the idea of a water filtration system using the air well technique would be of great interest in desert climates, especially those of a coastal nature.

Fog harvesting is another interesting thing, especially when they use trees such as casuarina to condense the water.

We live in the estern cascades with long hot rainless summers and we've been using rocks for this purpose to pretty great success.

While there is not a lot of natural dew in the summer times, the little bit of water we add to the trees increases transpiration so we have "dew pockets" that form. We're using native rocks for rock retaining walls, and also pile them in and around

here a pic of a rubble terrace wall in:

The rocks works wonderfully to capture the dew, and they do a whole lot else.

-they are the best mulch around as they don't absorb or wick any water and are completely impenetrable to plants and hold wate
-they collect water and channel it to the plants below them
-the provide a microclimete to get seeds established in very exposed areas (i've done this with alfalfa in open fields. pile rocks every few feet and seed the alfalfa, sheep sorel, perennial grass, right in the rocks.)
-they hold heat in winter and cool in summer, moderating temperatures so long as there is plant life to shade it. (plants get started earlier in the spring and produce later into the fall with the aid of the rocks)
-they crate habitat for all sorts of lizards, toads and bugs.

I first learned of these techniques from orchardists in the middle east who create large (20-100ft in diameter) craters, lined with stones (usually white limestone from what I read) at the center of which they planted an olive or pomegranite. The whole thing captured, held and channeled water for the benefit of the tree.

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> My family are taking on an allotment (community garden) this weekend which has limited
> access to water. As well as water storage tanks fed from the shed roof we're looking at
> alternatives. Does anyone have any experience with using air wells? I'd be grateful for
> any sources of info - online or books.

From williamevans at home.com Thu Aug 26 14:18:16 1999 Date: Thu, 26 ...
Using scrap and local materials, makeshift air wells could help solve
many water problems in drought ridden areas of the world, especially in
Third World ...
www.ibiblio.org/ecolandtech/orgfarm/permaculture/air-wells - 3k - Cached
- Similar pages

sounds like "water utilization"should read "efficiency"(same as)...
so for a given rainfall, one would look at amounts of runoff, amounts
evaporated, stored to aquafier either natural or manmade,amounts of
environmentally beneficient transducers(trees, plants, etc.), amounts
transpired thru the vegetation/evaporated from the soil,etc, etc...
how one could crunch this all down into a mathematical model is beyond
me....but here's some info i cullled from the net....courtesy of
http://www.tiac.net/users/seeker/creative.html """........Another interesting invention that has never been implemented
on a large scale was designed in 1931 by M.
Achille Knapen. He succeeded in condensing and extracting water from
warm air to irrigate fields and vineyards in
southern France with what he called, an "air well" (See U.S. patent no.
1,816,592). Looking like a 40-foot concrete beehive, it was possible to produce as much as 6,000 gallons of water
daily for every 1,000 square feet of
condensing surface. An airwell can be built on practically any scale,
and the wall materials can be concrete blocks,
bricks or concentric hollow shells filled with sand or earth. A small
airwell 12 feet high and 12 feet across with walls
2 feet thick can supply a generous output of daily water. It can be
fitted with top and bottom air pipes, and a
multitude of condensing plates on the inside. Warm air circulates and
gives up moisture on the cool inside
condensing plates angled downward toward a catch basin at the bottom
were it is collected. Using scrap and local
materials, makeshift air wells could help solve many water problems in
drought ridden areas of the world, especially
in Third World countries. """
bill evans

i started a project a couple of years ago with a solar panel and broken (reused) dehumidifier. i don't remember exactly, but i think i got about a half gallon per day. i would have gotten more, but the dehumidifier kept icing over. i have a 250 gallon, plastic water tank that i was filling from the gutter during the spring, then i wanted to top it off every day with this system. i have 3 raised beds with micro drip (and now with Hugelkultur) and wanted to connect the microdrip to the big tank and let gravity handle the rest.

This is an interesting idea. It reminds me of the reverse of an evaporation cooler where the outer wall (generally sand or porous stone) is whetted and the water evaporates, cooling the inside of the container. Too bad you couldn't cycle the whole idea as the refrigerator requires an arid climate and the water well requires a humid one.

It's amazing just how much this inspired me! Makes me wish even more that I had my own property on which to experiment. Just because I live on the top floor of a three story apartment doesn't mean I can't try my hand at designing something like this. Maybe I could get a friend of mine who lives in Montana to give my designs a try on her property and record the success or failures...

I also wonder if you could do something like a portable air well that could be easily set up and or moved if needed for say survival situations. At the very least maybe include information on air wells in survival training information so that in desperate measures if folks find themselves lost in the woods or wilderness without water they might be able to do a make shift version that could save their lives.

Much to think about and consider, thank you so much for posting this thread Paul. Amazing, simply amazing.

This is a brilliant technique for acquiring water when it refuses to fall from the sky, as it currently is doing in Central New Mexico. I have watched the rainfall amount in my region go from the "abundant" and "normal" yearly amount of 11 inches a year, last seen in 2007 with 10.22", from that high we have seen our yearly total dwindle...2008-8.36, 2009-6.67, 2010-8.94, 2011-4.7 and 2012-5.46.

I will be experimenting with various types of air wells to see what works best. If I can get a few established around my main trees and planting areas, I hope to reduce the well water I am currently expending to water these plantings and save on two fronts.

Im getting really interested in air wells,i run an track hoe at work so everyday i bring home the rocks i dig up that i can handle by hand, im stacking them up hill from my fruit tree i planted.
If i get enoungh id like to create a airwell by my garden.

Tom Brown uses a method similar to the Waterboxx for getting water out of the earth via condensation. Basically, you dig a hole, place a container in the center at the bottom, and cover the hole with a piece of plastic secured around the edges with dirt & rocks. Placing a small rock in the center of the plastic creates enough of an angle for the condensate to drip into the vessel below.

Adapting the rock pile idea to keyhole beds and other masonry edged beds is really a no-brainer, and kinda already standard practice. One more reason to use and reuse local materials for conservation!

I live in Arizona and been stacking rocks .5 meters high and six inches deep. I then mulch heavy I did this originally for habitat now I know why things wanna live there. Maybe I could build a rock pile house for me too ?

Very interesting and important thread here! I am sorry to say I have not visited for awhile as I have been swallowed up by face book in the last year or so. But I have been looking at many types of ancient rock structures, photographed and shared by face book friends all over the world, and often nobody knows what the structure was for, and ideas about the intended purpose vary widely. I can see now some of us have been puzzling over ancient "air wells". I will be happy to pass the information along. Sadly, my own southern PNW land is rock-free, so in order to put these ideas in practice during the dry summer months, I will have to import rocks.

In some areas of the Madawaska Valley in Eastern Ontario, fields have been cleared of rocks and boulders for generations and piled in long rows as fences on the edges of fields and pastures. I had noticed long ago that even in the summer dry periods there swathes of green on either side of these barriers, which, unmortared and about 3'-4' high, have been acting as air wells since new Polish immigrants were settled there to build railroads during the resource booms of that era.

From what I know of the Waterboxx and similar, likely older, water gathering methods, they use the sun to evaporate moisture from the hole or a container separate from the collection bowl. Modern survivalists (read: people accidentally finding themselves without water in a desert situation, not preppers) use this method to reclaim water from urine and other unpotable sources. This, however, only resembles air wells in that a temperature drop when the evaporate hits the colder surface results in condensate. It is a valid, but unrelated, development.

I came across these in Volcano national Park in Hawaii -- one of nature's versions of pulling water from the air.
To me it was neat b/c I have heard of people creating them, I was amazed that it occurred on it's own.
The pictures didn't really capture how much life was there, but since the rest of the area looked like a parking lot of newish lava, I was astounded.
The pocket is shaped like a bridge and the air flows through, cools down and water condenses out and drips to the plants. You can kind of see the opening on the other side near the top of pic 2, a little light pokes through.

Really glad I followed this thread, it is fascinating ... I climbed around the underground cities near Goreme in Turkey, years ago, (and love the "Dune" series) and the wind/water traps caught my imagination then... and now. Thanks for the thoughtful comments and links, everybody

Cassie Rauk wrote: At its simpliest an air well is a structure or a device that collects water from the air using condensation. In the early part of the 1900, a few enterprising men experimented with rock air wells to capture moisture. They were working off the theory ancient cities used stacks of rocks as condensers and terra cotta pipes connected to the city’s water system to supply water for the city.

Interesting, that in ancient times they were used for drinking water and not crops. Perhaps there was much less desertification. I would suggest that proper land management would change the amount of rainfall in these places, or at least make any large air wells not needed. A city/town/village is by nature an "unnatural" place in the middle of nature, so supplementing other water catchment systems in this manner makes more sense. I get the idea from seeing things like "Greening the desert" and the works on using livestock to halt/reverse desertification, that airwell technology might help get things started, but should not be needed long term in a polyculture/permaculture setup. Though perhaps if the plot of land you have is an island (small one at that) in the middle of a monoculture desert it could be one more tool that helps.

Are there issues with pollution/chemicals in the air? Do they condense out as well?

Chris Kott

Joined: Jan 25, 2012
Posts: 796
Location: Toronto, Ontario

9

posted Apr 06, 2013 13:11:49

0

I'm pretty sure that anything that evaporates with water will condense under the same conditions, so yes. But if, for example, there was a layer of biochar that the condensate ran through, and/or filtration through sand layers, or depending on the specific situation perhaps a swale system heavily planted with reed species and other water cleaning aquatic plants, any of these steps could be used to clean the condensate.

I like the method I described above, which was simply a way to get rocks out of the fields and pastures and to make use of available materials to build a necessary barrier; its water-collecting merits probably remain unknown except as a curiosity noticed by the owners. I was actually thinking that on a property with a lot of loose rock, I will probably experiment with adding an outer shell of unmortared stacked stone, at least two courses deep, on all but the southern sides of hugelbeets that will form the perennial fruit and nut tree polyculture rows in an food forest/pasture alley cropping plan. In this way, I hope to not only recover much of the moisture transpired by the vegetation, but also to trap the heat of the hugelbeet and incoming sun, as well as any added by ongoing decomposition.

It has also occurred to me that a nearly vertical stone airwell wall would make an excellent north wall for a modified east-west oriented hugelbeet with a south-facing slope terraced in steps one stone high. I think to be truly useful to, say, reverse desertification, airwells need to be combined with an ecosystem that can take up the water and use it to support life and promote fertility. I could see a properly designed airwell and hugelbeet not only providing moisture for itself, but enough to encourage the growth of shading plant life, up to trees and shrubs, forming oases with damp depressions that become dewponds, and then more. More vegetation translates to more transpiration, and more condensation within the airwell. As long as someone prepares the depression to properly hold water, we could be talking about little lake-making machines.

On lanzarote (canary island) A similar way of propagating is practised in the local vinyards like the pictures of Hawai show. They dig holes in the vulcanic rock and plant a vine at the bottem.

Len Ovens
pollinator

Joined: Aug 26, 2010
Posts: 1330
Location: Vancouver Island

18

posted Apr 06, 2013 16:15:53

0

Chris Kott wrote:I'm pretty sure that anything that evaporates with water will condense under the same conditions, so yes. But if, for example, there was a layer of biochar that the condensate ran through, and/or filtration through sand layers, or depending on the specific situation perhaps a swale system heavily planted with reed species and other water cleaning aquatic plants, any of these steps could be used to clean the condensate.

I would guess the same steps would need to be taken with any kind of water catchment system. I like the ideas like those, which don't require replaceable filters.

Stone-age? I suspect a lot of these things are pre-stone-age, and used by nature before Man. (see the pictures up a bit of the volcanic version)

"cursed is the ground for your sake. In toil you will eat of it all the days of your life. Thorns also and thistles will it bring forth to you; and you will eat the herb of the field. By the sweat of your face will you eat bread"

Paraphrase:
cursed is the ground because of man. Because you toil on the ground and till it to grow grain for bread, there will be thorns also and thistles and other weeds and your topsoil will blow away to make desserts.

Be it Prophesy or a story passed down about Man's beginnings, (choose your own belief) it describes where we are well. Here we are eating bird food (seeds) which we have to process to make digestible from a farming practice that has destroyed vast areas of the world. Are we ever stupid...

Chris Kott

Joined: Jan 25, 2012
Posts: 796
Location: Toronto, Ontario

9

posted Apr 06, 2013 16:57:26

0

Please tell me that's not out of the King James. The same edition has some apalling mistranslations.

As to interpreting scripture, I think to get anything close to the original meaning, one would have to study one of the first half-dozen languages into which it was first written, and preferably like the first half of that, for accuracy. Keeping in mind, of course, that if you went back like 500 years or so in our own language, I doubt it would be recognizable to someone who hadn't studied it. If that progression was constant across all languages and on average the same rate of change, and you went back to whenever it was the New Testament could be had in a one-volume set (I'm cheap), you'd need a Rosetta stone of your own.

It's muddy, is all I'm saying. Plus, there's a big black book, or manual, if you will, that contains within its pages a wealth of information as important, and in some practical terms much more relevant, in my considered opinion.

-CK

Len Ovens
pollinator

Joined: Aug 26, 2010
Posts: 1330
Location: Vancouver Island

18

posted Apr 06, 2013 17:58:02

0

Chris Kott wrote:Please tell me that's not out of the King James. The same edition has some apalling mistranslations.

No, not KJV, though it probably dosn't matter. Certainly the parts I refer to would originally be in hieroglyph, not phonetic spelling which showed up much later. However, that was not the point. The idea that man has spoiled the land does seem to be an old one though.

Chris Kott

Joined: Jan 25, 2012
Posts: 796
Location: Toronto, Ontario

9

posted Apr 06, 2013 20:49:04

0

I have always found it interesting that the Babylonians (post-Hammurabi, anyway) thought of life as decline from a Golden Age, though.

bj henkes wrote:On lanzarote (canary island) A similar way of propagating is practised in the local vinyards like the pictures of Hawai show. They dig holes in the vulcanic rock and plant a vine at the bottem.

Yes, they did dug first to reach the soil! Then for condensing water, protect from wind, forbid evaporation...

Another system in Tenerife! This works in altitude.

With plastic for collecting the horizontal rain from fog and "cloud sea".

I have a few old terra cotta drain pipes. Wondering if placing those in the middle of the rock pile would work better than just a random stack?

Hans Quistorff

Joined: Feb 25, 2012
Posts: 111
Location: Longbranch, WA

2

posted Apr 11, 2013 13:25:04

2

Scott Stiller wrote:I have a few old terra cotta drain pipes. Wondering if placing those in the middle of the rock pile would work better than just a random stack?

From the illustrations in this thread it seems that a downdraft chimney in the middle of the stack improves night time cooling. If you have experienced smoke coming out of your cold stove because warm air was escaping from your house and drawing cold air down the chimney, you know how powerful this can be.
Therefor I suggest that any scrap pipe placed in the center of a large pile with air outlet at the bottom by placing it on the edges of triangle of spaced rocks at the stack would increase the efficiency.